Uneven particle system fall on a mesh object
To the rotation problem: you can change in the rotation tab the phase, which rotates all particles in the same angle. You can then randomize the phase a bit to get a more realistic result.
To your distribution problem: I cant really give you a solution for that. I recently ran into similiar problems. What i can tell you is, you need a god topology for the particle system, so more or less even size of your faces (maybe use a remesh modifier). I personally fixed my problem with the weight paint and the distribution by starting over with a complete new emitter object...